Red ink on Black T-shirts?

Standard Speedball red ink for fabric block printing just isn't doing the job on black T-shirts. It works just fine on other colors, but just isn't bright enough on a black T-shirt (same brand as others).

I tested this on several other shirts and colors, and it's just black I have trouble with. Methodology is

• flatten shirt
• Insert foamcore board between the t-shirt layers
• moisten the area of the t-shirt I want to print at with a small spray bottle. Not to much because it will bleed, and not to little because it won't absorb
• Using a standard pink rubber carving
• Made several test prints first as people have mentioned that sometimes you need to prime your block.
• Used more ink than if I were doing this on paper. More of an orange skin, than little dots.
• Placed the stamp on top of the shirt
• Used a 1 by 4 by 18 inch board to press down on the block (Works well on other prints)
• And it still wasn't opaque :-(

Any suggestions?